For the record, I enjoy both TOS and TNG...but one thing that always bugged me about TNG was the way it swapped the Klingon and Romulan traits established in TOS. Romulan culture, as portrayed in the TOS episode "Balance of Terror", was as a complex, honor-driven society and it was the Klingons who were hostile, scheming, and warlike. I read an interview years ago with a TNG writer whose name I don't remember who said something along the lines of "we thought it would fun to get creative and swap the traits of the Klingons and Romulans".
I thought it was neither fun, nor creative.
BOT established a couple of Romulans were honorable, but also implied they were out of step with the rest of Romulan society.
This is after all a society that uses the sneak attack as a primary tactic. To quote Spock:
Balance of Terror wrote:
Earth believes the Romulans to be warlike, cruel, treacherous
I doubt much complexity was ever present in the two times we actually saw Romulans on TOS.